If the question is can you have romance with superheroes, well we saw how long the Parker Marriage lasted and that certainly had a lot of romance genre elements to it, even if writers weren't actively trying to sell on that idea. Then there was the time before with the Fantastic four when Sue and Reed weren't married and the courtship between the two was played up (wouldn't mind having a romance book with those two in the lead). As for right now, one of the biggest selling books and certainly has a large fandom is Sailor Moon, which relies on the idea of love and romance being a key element in the over all story along with the lead characters being seen as superheroes as well.
Manga does certainly sell to women because in a lot of cases the writers don't shy away from the idea of an end couple in some cases. Naruto, for example, even though a majority of the story focuses on Naruto and Sasuke's story, there's a large element in there about the feelings that the led three characters go through. That's nothing to say about Avatar the last Air bender.
Let's not forget that JRSr. was brought on to spiderman due to the fact that prior he had been drawing Romance comics and knew how to make the characters look really good. Saga right now is in the top spot, and isn't that majorly a scifi romance in the first place?
I'm all for those books that you mentioned, but are they being billed as such? I can't remember. And Yes I would love a spiderman loves MJ book to come back! I thought that was a good idea and the fact is a good portion of readership would be okay with reading a bit of a slice of life meets superheroics. I mean if TV shows are anything to go by or the fact that YA books are outselling most adult novels then you'd think that, you know, Marvel would go "Maybe there's something here?"
Zombie survival I count more as survival in general rather then straight up horror. You would think Marvel would want to try to have maybe a group of the magic users in Marvel team up. That would make for an interesting book covering all sorts of things that the normal books can't cover. JIM sort of worked with this a bit.
Andy: Gotta agree with you, I like Moon Knight but like Batman writers have pulled away from the idea that they're detectives and focused more on already letting the reader know who's the big bad. that's sort of the point of the mystery, and given that there have been detectives in the past, and certainly case closed shows you can do a long ongoing mystery series in comics form now, I don't see why they're not taking a chance?